Wheel disk assembly having simplified sealing-plate mounting

ABSTRACT

A wheel disk assembly, having a wheel disk, a plurality of blade devices, which are fastened along the outer circumference of the wheel disk, and a plurality of sealing plates, which are retained in two annular grooves radially spaced apart from each other. A first annular groove is in the wheel disk and a second annular groove is formed by the blade devices in a segmented manner. Simplified mounting of the sealing plates is achieved in that the first annular groove is expanded by an axially extending recess.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the US National Stage of International ApplicationNo. PCT/EP2016/050343 filed Jan. 11, 2016, and claims the benefitthereof. The International Application claims the benefit of EuropeanApplication No. EP15156321 filed Feb. 24, 2015. All of the applicationsare incorporated by reference herein in their entirety.

FIELD OF INVENTION

The present invention relates to a wheel disk assembly having a wheeldisk and a plurality of blade devices fastened on the wheel disk and aplurality of sealing plates fixed in an annular slot on the wheel disk.

BACKGROUND OF INVENTION

Wheel disk assemblies of the type referred to in the introduction areknown in the prior art in a very wide variety of embodiments, wherein ina conventional embodiment a wheel disk has on the outer circumference aplurality of blade-root-locating slots which extend in the direction ofthe disk axis. Blade devices are arranged in these by their blade root.For the end-face covering of the blade-root-locating slots, sealingplates are inserted and for this purpose are generally mounted inannular slots. GB 905,582 A discloses a typical example of this. In thiscase, the wheel disk has an encompassing, outwardly open, inner annularslot in which is axially fixed an end of the sealing plate which pointstoward the disk axis. On the opposite outer end of the sealing plateprovision is made for an inwardly open outer annular slot. The outerannular slot is formed by the blade devices which are adjacent to eachother in the circumferential direction.

During installation, the blade devices are inserted into theblade-root-locating slots of the wheel disk, wherein the sealing platesare also inserted in succession between the two annular slots. In orderto be able to install the last two blade devices, all the sealing plateshave to be already mounted beforehand and be displaced in the annularslots via their overlapping regions by such a distance that the bladedevices can be installed in the associated slots of the wheel disk. Thesealing plates are then pushed back again in the circumferentialdirection into their designated position and suitably secured thereagainst a displacement in the circumferential direction.

A disadvantage of the known wheel disk assemblies exists in the factthat the sealing plates in the event of a service can only be removedwith difficulty since two adjacent blade devices have first of all to beremoved which in practice is accompanied by a considerable cost.

SUMMARY OF INVENTION

Starting from this prior art, it is an object of the present inventionto create a wheel disk assembly of the type referred to in theintroduction, in which a greater degree of flexibility is achieved withregard to the mounting of the sealing plates.

The generic wheel disk assembly comprises a wheel disk, a plurality ofblade devices and a plurality of sealing plates. The wheel disk has inthis case a blade-locating section which is arranged on the outercircumference. Fastened on this, in a detachable and circumferentiallydistributed manner, are the blade devices. Furthermore, the wheel diskhas an annular projection which is at an axial distance from theblade-locating section. An annular slot is arranged between theblade-locating section and the annular projection. The sealing plates,by an edge region pointing toward the disk axis, are mounted in theannular slot and fixed in the axial direction by means of theblade-locating section and the annular projection. The disk axisobviously corresponds to the central rotational axis of the rotor disk.The edge region of the sealing plates is adjacent to the end of thesealing plates which points toward the disk axis and extends radiallyvertically corresponding to its arrangement in the annular slot.

For achieving the object, it is provided according to the invention thatthe annular slot is widened in the axial direction by at least onerecess which defines a sealing-plate-mounting region. In this respect,the recess extends from the annular slot in the axial direction into theblade-locating section and/or into the annular projection. In this case,it is necessary that the length of the recess in the circumferentialdirection is greater than the length of the sealing plates in the edgeregion.

Thanks to such a recess, the sealing plates can be threaded in a simplemanner into the associated annular slots, even if all the blade devicesare already mounted on the wheel disk, as a result of which the mountingis designed in a very flexible manner. In this case, the sealing platescan be inserted by the edge region for example at an angle from aboveinto the recess and the sealing plate can then be tilted in thedirection of the wheel disk. After that, the sealing plate can be movedin the circumferential direction along the annular slot. By the sametoken, the individual sealing plates can be removed again in a simplemanner in the reverse sequence.

It is basically irrelevant in the first instance whether the annularslot is of segmented and/or discontinuous design provided that thediscontinued regions are not required for attaching a sealing plate. Inboth a simpler and particularly more advantageous embodiment, theannular slot in cross section—apart from the recess—is of constantlyencompassing design.

According to one embodiment of the present invention, all the sealingplates are identically designed as identical parts, as a result of whichthe production and also the storage of the sealing plates aresimplified.

It is particularly advantageous if the recess also extends in the radialdirection pointing toward the disk axis. That is to say that the recessover a limited length enlarges the cross section of the annular slot inthe axial direction and in the radial direction.

As a result of the enlargement which is provided both in the axialdirection and in the radial direction by means of the recess, anadvantageous free space is created for mounting the sealing plates bytheir edge region. In particular, it is possible to first of all insertthe sealing plates into the recess in such a way that these arepositioned closer to the disk axis than in line with the end position.The sealing plates can subsequently be outwardly displaced in the radialdirection and therefore be relocated into the end position.

The annular projection, on the side facing the annular slot,advantageously has a bevel in the region of the recess, wherein thebevel is designed so that the annular projection is flattened toward theannular slot. Such a bevel also simplifies the insertion and removal ofthe sealing plates in the region of the recess.

According to one embodiment of the present invention, the annularprojection, on the side facing the annular slot, has in the region ofthe recess an undercut region in the form of a cavity which is opentoward the annular slot.

Provision is advantageously made for two recesses which are formeddiametrically opposite one another in the wheel disk. Thanks to a secondrecess, imbalances can be avoided during the designated installation ofthe wheel disk assembly. Furthermore, the sealing plates can be mountedand removed more quickly. Also conceivable is the arrangement of amultiplicity of recesses which are to be distributed over thecircumference rotationally symmetrically to the disk axis.

According to one embodiment of the present invention, the annular slotis of undercut design and, as seen in cross section, has at least oneretaining projection which projects axially in the direction of thesealing plate. The retaining projection is correspondingly selectivelylocated on the blade-locating section and/or on the annular projectionand is arranged radially outside the annular slot. In this case, theretaining projection has a retaining surface on the side pointing towardthe annular slot, i.e. toward the disk axis. It is irrelevant in thefirst instance whether retaining projections are provided on one side oron both sides and whether one retaining surface or a plurality ofretaining surfaces are provided on the retaining projection. Theembodiment with a retaining projection extending circumferentially alongthe annular slot, with a retaining surface arranged thereon, is bothadequately and advantageously simple. Corresponding to this, the sealingplates in the edge region have at least one axially projecting supportprojection which is provided with a support surface. Therefore, the edgeregion with the support projection acts as a thickening for the regionof the sealing plate which lies radially outside the edge region.

The retaining surface of the retaining projection and the supportsurface of the support projection are arranged in such a way that thesupport surfaces of the sealing plates, during the designated operationof the wheel disk assembly, are supported against the retaining surfaceof the retaining projection under the influence of a centrifugal force.Thanks to this embodiment, the natural weight of the sealing platesunder the influence of a centrifugal force is absorbed by the wheeldisk, as a result of which the blade devices are relieved of load.

Provision is made for at least one filler piece which is arranged in therecess. By means of the filler piece, it is possible to prevent aninadvertent slipping out of the sealing plate from the annular slot or apartial deformation of the sealing plate in a position in which thesealing plate is arranged over a part of the length in the region of therecess. To this end, it is necessary that the filler piece butts againstthe sealing plate.

In this case, it is advantageous on the one hand if the filler piece bya radially extending contact surface butts axially against the edgeregion of the sealing plate. Therefore, the axial fixing of the sealingplate is also ensured in the region of the recess.

Furthermore, it is advantageous if the filler piece has an axiallyextending contact surface pointing radially outward, against which aninner circumference of the sealing plate butts. Correspondingly, thesealing plate in the region of the recess can be supported on the fillerpiece and, especially in the case of a recess which extends radiallyinto the wheel disk, is not displaced toward the disk axis with the diskassembly stationary for example.

The filler piece is advantageously designed in such a way that a bevelprovided on the annular projection is filled out. As a result of this,on the one hand, imbalances as a result of material gaps which otherwiseexist on one side are prevented, and in particular a better support ofthe filler piece is provided by the sealing plate in the event of anaxial load.

Furthermore, it is advantageous if the filler piece, with provision of acavity which opens toward the recess, projects into this cavity. Onaccount of the undercut design in this region as a result of the cavity,the radial fixing of the filler piece can be achieved.

In a particularly advantageous embodiment, the blade devices have ineach case an annular slot segment which extends in sections around thedisk axis and is open radially toward the disk axis. In this case, it isprovided that the sealing plates are accommodated on their outercircumference in the annular slot segments and in this case are fixed inthe axial direction. In this case, it is irrelevant whether provision ismade on the sealing plate for further contours which are arrangedaxially next to the outer circumference considered here. Essentialinstead is a securing of the position of the sealing plate on the outercircumference in the direction of the disk axis.

Taking into consideration the advantageous recess which extends radiallyinto the wheel disk, this leads to a mounting in which the sealing plateis first of all lowered into the recess and after pivoting or pushing ismoved radially outward onto the wheel disk. With this, the insertion ofthe sealing plate by the outer circumference into the annular segmentsis then carried out. In this case, it is irrelevant whether a sealingplate is accommodated in each case in an annular slot segment or whetherthe sealing plates are advantageously arranged in an overlapping mannerin relation to the blade devices and in this respect engage in adjacentannular slot segments.

The sealing plates advantageously have in each case a circumferentialdisplacement lock which holds the corresponding sealing plate in thedesignated position during the designated use of the wheel diskassembly, that is to say prevents a displacement in the circumferentialdirection.

According to one embodiment of the present invention, the sealing plateshave a hole and the wheel disk has associated openings, whereinconnecting elements which extend through the holes engage in theassociated openings and in the process are advantageously fastened onthe sealing plates. Thanks to the fixing of the connecting elements onthe sealing plates, an unnecessary weakening of the wheel disk as aresult of notch effect or the like is prevented. The opening isadvantageously designed in the form of a radially extending elongatedhole. Correspondingly, the sealing plates can move radially outwardunder the influence of a centrifugal force during the designated use ofthe wheel disk assembly.

According to one embodiment of the invention, a multiplicity of edgesand corners of the first annular slot and/or of the support protrusionsand/or of the filler piece are provided with radii. As a result of suchradii, a weakening of the corresponding component as a result of notcheffect is avoided.

The present invention furthermore creates a method for installing awheel disk assembly according to the invention, in which method all theblade devices are fastened on the wheel disk in a first step, and thesealing plates are mounted in a further step.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present invention will becomeclear based on the following description with reference to the attacheddrawing.

In an exemplary embodiment for a wheel disk assembly according to theinvention:

FIG. 1 shows a perspective view of a wheel disk assembly;

FIG. 2 shows a perspective view of the wheel disk in the region of therecess;

FIG. 3 shows a cross section through the wheel disk in the region of therecess;

FIG. 4 shows a view similar to FIG. 2 with sealing plate inserted;

FIG. 5 shows an enlarged perspective sectional view through the recesswith sealing plate and inserted filler piece;

FIG. 6 shows a cross section for the embodiment from FIG. 5;

FIG. 7 shows a side view of the filler piece for FIG. 5;

FIG. 8 shows a perspective view for FIG. 5;

FIG. 9 shows a perspective sectional view similar to FIG. 5 with analternative design of the recess and of the filler piece.

DETAILED DESCRIPTION OF INVENTION

FIGS. 1 to 8 show a wheel disk assembly 1 and its components accordingto a first embodiment of the present invention. The wheel disk assembly1 comprises a wheel disk 2, a plurality of blade-devices 3 which arefastened along the outer circumference on a blade-locating section 24 ofthe wheel disk 2 in associated axially extending blade-root-locatingslots 4, and a plurality of sealing plates 5 which are retained betweenthe wheel disk 2 and the blade devices 3 in radially spaced-apartannular slot and annular slot segments 6, 7. The annular slot 6 is inthis case provided in the wheel disk 2 and is delimited axially outwardby means of a continuous annular projection 8. Formed opposite theretoin each case in the blade devices 3 is an annular slot segment 7.

The annular slot 6 which is provided in the wheel disk 2 is of undercutdesign and, as seen in cross section, has an axially projectingretaining projection 9 which projection 9 is provided with a retainingsurface 10. Correspondingly, the sealing plates 5 in an edge region onthe inside diameter, as seen in cross section, have an axiallyprojecting support projection 11 which is designed to correspond to theretaining projection 9 and which projection 11 is provided with asupport surface 12.

For facilitating the mounting of the sealing plates 5, two recesses 13(of which recesses 13 only one recess 13 is shown in the figures), whichare diametrically opposite each other and of identical design and ineach case define a sealing-plate-locating region, are arranged on theannular slot 6. The length of the recess 13 in the circumferentialdirection is greater than the width of the sealing plates in the edgeregion which is accommodated in the annular slot 6. The recess 13extends in the axial direction and widens the annular slot 6. Theannular projection 8, on the side facing the first annular slot 6 in theregion of the recess 13, has a bevel 14 which bevel 14 is designed insuch a way that the annular projection 8 is flattened toward the annularslot 6.

The wheel disk assembly 1 also comprises a filler piece 15 which fillerpiece 15 is designed in such a way that it fills out the region which iswidened in relation to the annular slot 6 by the recess 13 as well asthe region of the bevel 14. Furthermore, the filler piece 15 has aprojection 16 which axially points away from the annular projection 8,extending beneath a sealing plate, and therefore defines an axiallyextending contact surface which serves for the location of an innercircumferential edge of at least one sealing plate 5. The recess 13which also extends radially into the wheel disk 2 breaks up the base ofthe annular slot 6 which is otherwise provided in an encompassing mannerfor the seating for the sealing plates 5. By means of the axial contactsurface, a basically flush seating for the sealing plates 5 in theregion of the recess 13 is created.

The sealing plates 5 are designed identically in each case and comprisea hole 17 in each case through which hole 17 extends a connectingelement 18 of basically pin-like design in the designated installedstate of the wheel disk assembly 1, which connecting element 18 isfastened on the associated sealing plate 5 and engages in an opening 19,in the form of a radially extending elongated hole, which is formed onthe wheel disk 2.

During the installation of the wheel disk assembly 1, all the bladedevices 3 are mounted on the wheel disk 2 in a first step. In a furtherstep, the sealing plates 5 are installed one after the other. To thisend, each sealing plate 5 is inserted by its edge region from above intothe recess 13 and then tilted in the direction of the wheel disk 2.After that, the sealing plate 5 can be moved upward, i.e. radiallyoutward, then inserted by its outer circumferential edge into theannular slot segments 7 and then moved in a guided manner in thecircumferential direction between the annular slot 6 and the annularslot segments 7. In this case, the individual sealing plates 5 are firstof all pushed one on top of the other in the circumferential directioninto overlapping regions so that after the mounting of the last sealingplate 5 the sealing-plate-mounting region which is defined by the recess13 remains free. In a further step, the filler piece 15 is then insertedinto the recess 13. Next, the sealing plates 5, which are arrangedadjacently to the recess 13, are to be pushed in each case in thecircumferential direction one onto the other so that in each case theylie half on the projection 16 of the filler piece 15. Now the fillerpiece 15 is secured against an inadvertent detachment by means of theoverlying sealing plates 5. In a further step, the connecting elements19 are pushed through the holes 17 of sealing plates 5 so that theconnecting elements 19 engage with the associated openings 18 which arepositioned in each case in alignment with the holes 17. The connectingelements 19 are then fastened, for example by peening, to the sealingplates 5. Now the sealing plates 5 are secured against an inadvertentdisplacement in the circumferential direction.

During the designated operation of the wheel disk assembly, acentrifugal force acts upon the sealing plates 5, which leads to thesealing plates 5 moving radially outward, wherein the connectingelements 19 are guided inside the associated openings 18. The radiallyoutward movement of the sealing plates 5 is limited by the supportprojections 11, which are formed on the sealing plates 5, as soon as thesupport surfaces 12 of the support projections 11 come to butt againstthe retaining surfaces 10 of the retaining projections 9 of the wheeldisk 2. In this state, the wheel disk 2 then absorbs the forces whichare created by the natural weight of the sealing plates 5.

An essential advantage of the previously described wheel disk assembly 1exists in the fact that the sealing plates 5, thanks to the recesses 13,can be threaded into the associated annular slots 6, 7 in a simplemanner, even if all the blade devices 3 are already mounted on the wheeldisk 2, as a result of which the mounting is designed to be veryflexible. By the same token, the sealing plates can also be removedagain in a simple manner. A further advantage exists in the fact thatforces, which under the influence of centrifugal force are created as aresult of the natural weight of the sealing plates 5, are absorbed bythe wheel disk 2 thanks to the retaining projection 9 which is providedon the wheel disk 2 and to the support projections 11 which are formedon the sealing plates 5, as a result of which the blade devices 3 arerelieved of load to a high degree during operation of the wheel diskassembly 1.

FIG. 9 shows an alternative embodiment of a recess 20 and of a fillerpiece 21 which is inserted into the recess 20. The recess 20 differsfrom the depicted recess 13 to the effect that the annular projection,on the side facing the annular slot 6 in the region of the recess 20,has an undercut region with a cavity 22 which is open toward the recess20. The filler piece 21 differs from the filler piece 15 to the effectthat this also fills out the undercut region, i.e. the cavity 22, andthat in contrast to the filler piece 15 there is no provision for aprojection 16 pointing away from the annular projection upon which restthe sealing plates 5. Otherwise, the embodiment shown in FIG. 9corresponds to the previously described wheel disk assembly 1, which iswhy the same component parts or components are identified by the samedesignations.

Although the invention has been fully illustrated and described indetail by means of the preferred exemplary embodiment, the invention isnot limited by the disclosed examples and other variations can bederived by the person skilled in the art without departing from theextent of protection of the invention.

1. A wheel disk assembly comprising: a wheel disk which has ablade-locating region and at least one annular projection spaced apartin the axial direction and at least one annular slot which is arrangedbetween the blade-locating section and the annular projection, and witha plurality of blade devices which blade devices are fastened on theblade-locating section in a circumferentially distributed manner, andwith a plurality of sealing plates which sealing plates, by the edgeregion pointing toward the disk axis, are fixed in the annular slot inthe axial direction, and a recess which recess extends from the annularslot in the axial direction into the blade-locating section and/or intothe annular projection and the length of which in the circumferentialdirection corresponds at least to the length of the edge region of thesealing plates.
 2. The wheel disk assembly as claimed in claim 1,wherein the recess furthermore extends from the annular slot pointingtoward the disk axis.
 3. The wheel disk assembly as claimed in claim 1,wherein the annular projection has a bevel sloping toward the recess. 4.The wheel disk assembly as claimed in claim 1, wherein the annularprojection has a cavity which opens toward the recess.
 5. The wheel diskassembly as claimed in claim 1, wherein provision is made for two ormore recesses which are arranged rotationally symmetrically to the diskaxis.
 6. The wheel disk assembly as claimed in claim 1, wherein theblade-locating section and/or the annular projection have/has aretaining projection which is arranged radially outside the annularslot, extends axially to the sealing plate, and has a retaining surfacepointing toward the annular slot, and in that the sealing plate on atleast one side has a projecting support projection having a radiallyoutwardly pointing support surface, wherein the support surface, atleast in the event of a centrifugal force acting upon the sealing plate,butts against the retaining surface.
 7. The wheel disk assembly asclaimed in claim 1, further comprising: a filler piece which is arrangedin the recess, extends in sections in the circumferential direction andbutts against the sealing plate.
 8. The wheel disk assembly as claimedin claim 7, wherein a radially extending contact surface and/or anaxially extending contact surface of the filler piece butts against thesealing plate.
 9. The wheel disk assembly as claimed in claim 7, whereinthe filler piece projects into the bevel and/or into the cavity.
 10. Thewheel disk assembly as claimed in claim 1, wherein the blade deviceshave in each case an annular slot segment which is open radially towardthe disk axis, wherein the sealing plates are fixed in the axialdirection on their outer circumference in the annular slot segments. 11.The wheel disk assembly as claimed in claim 1, wherein at least onesealing plate is secured in the circumferential direction by means of acircumferential displacement lock.
 12. The wheel disk assembly asclaimed in claim 11, wherein at least one sealing plate for securing inthe circumferential direction has a hole and the wheel disk has anassociated opening, wherein a connecting element engages in the openingthrough the hole.
 13. The wheel disk assembly as claimed in claim 1,wherein all the sealing pates are secured in the circumferentialdirection by means of a circumferential displacement lock.
 14. The wheeldisk assembly as claimed in claim 13, wherein all the sealing plates forsecuring in the circumferential direction have a hole and the wheel diskhas an associated opening, wherein a connecting element engages in theopening through the hole.